1. Field of the Invention
This invention relates to a catalyst for catalytic combustion of a fuel. More particularly, the present invention relates to an advanced ceramic catalyst made by metal oxides dispersed in refractory ceramics and the process of making same.
2. Description of Related Art
Metal oxides have been known for many years to act as catalysts in reaction related to combustion, byproduct of combustion and many other chemical reactions. Metal oxides like Cobalt (Co), Nickel (Ni), Molybdenum (Mo), Zinc (Zn), Iron (Fe), Copper (Cu), Titanium (Ti), Chromium (Cr), Tin (Sn), Antimony (Sb), Tungsten (W), Vanadium (V), etc., precious metals like Gold (Au) and Platinum (Pt), some Lanthanide like Cerium (Ce), Neodymium (Nd) and others.
There are several patents, patents applications and published studies about using metal oxides like Co, Ni, Mo, Zn. Fe, Cu, Ti, and Cr.
H. Furbeck, et al., “Manganese-based oxidation catalyst”, U.S. Pat. No. 7,208,128 (Apr. 24, 2007) discloses Raschig rings which are a mixtures of Mn3O4 and Al2O3 who were treated with phosphoric acid solution to improve the rings catalytic effect of oxidative destruction of Volatile Organic Compounds and carbon monoxide, the byproduct of a variety of commercial establishments.
S. Deevi, et al., “Catalysts for low temperature oxidation of carbon monoxide”, U.S. Pat. Application No. 20100068120 (Mar. 18, 2010) discloses a copper oxide-zinc oxide-cerium oxide catalyst precipitated together in solution by aging at 70° C. for at least 3 hours, filtered, washed, dried and calcined. Cerium oxide precipitated on copper oxide has the capability of carbon monoxide oxidation carbon dioxide. Catalyst with lattice defects capable of oxidizing carbon monoxide in cigarettes. It is assumed that the catalyst has some nanoparticle resulted in decomposition of aged precipitate. The composition of the oxide in the catalyst is 100%.
L. Borduz, et al., “Method of preparing low viscosity, electrically conductive ferrofluid composition”, U.S. Pat. No. 4,732,706 (Mar. 22, 1988) and K. Raj, et al. “Electrically conductive ferrofluid compositions and method of preparing and using same”, U.S. Pat. No. 4,604,229 (Aug. 5, 1986) discloses a low viscosity, electrically conductive ferrofluid composition where nanoparticles of magnetite is precipitated in solution covered with cationic surfactants, separated and dispersed in an oil to produce a final magnetic ferrofluid electrical conductible used in seal devices.
W. Pfefferle, “Thermal shock resistant split-cylinder structures”, U.S. Pat. No. 4,402,662 (Sep. 6, 1983) discloses a cylindrical structure monoliths ceramic with high coefficient of thermal expansion nickel doped stabilized zirconia. There is no claim of a particular catalyst, however, it is mentioned in the invention description that the catalyst is recommended to be ceramic oxide metal of the spinel type such as magnesium chrome and lanthanum chrome spinels specially selected to be able to make a curved shape as a cylinder.
H. Ishikawa, et al., “Method of preventing burning resonance noise and a burner plate”, U.S. Pat. No. 5,417,566 (May 23, 1995) discloses a burner plates having a multiple of fire holes adapted to dispose of burner chamber defining an acoustic system having characteristic frequency. A burner plate wherein the burner varies in thickness from its center outwardly.
W. Best, “Radiant burner utilizing flame quenching phenomena”, U.S. Pat. No. 3,277,948 (Oct. 11, 1966) discloses a unitary plate shaped member of refractory ceramic adapted for use in forming a radiant burner with the slot-shaped passage extending through substantially the shorter distance from the rear surface of the burner.
W. Milligan, “Catalytically active radiant tile”, U.S. Pat. No. 3,302,689 (Feb. 7, 1967) discloses a catalytically active radian theater tile comprising a highly porous refractory plate having an input surface and an opposed combustion surface, said refractory plate containing a combustion catalyst dispersed therein and having a pore volume area of at least 100 square meters per gram of plate. Has been also discover that the catalytic activity of common metallic oxides catalyst can be stimulated sufficiently to exceed even the noble metal catalyst.
W. Milligan, “Catalytically active radiant tile”, U.S. Pat. No. 3,302,689 (Feb. 7, 1967) discloses a catalytically active radian theater tile comprising a highly porous refractory plate having an input surface and an opposed combustion surface, said refractory plate containing a combustion catalyst dispersed therein and having a pore volume area of at least 100 square meters per gram of plate. Has been also discover that the catalytic activity of common metallic oxides catalyst can be stimulated sufficiently to exceed even the noble metal catalyst.
M. Partiot, “Deep combustion radiant surface gas burner”, U.S. Pat. No. 3,179,157 (Apr. 20, 1965) and M. Partiot, “Directional beamed radiant heaters”, U.S. Pat. No. 3,492,986 (Feb. 3, 1970) discloses a deep combustion radiant surface burner constructed to conduct combustible gas mixture to surface thereof and comprising a unitary block of refractory material having a myriad bore substantially straight elongated from the first to the second boundary surface.
F. Tang, et al., “Catalyst and process for the conversion of carbon monoxide”, U.S. Pat. No. 6,019,954 (Feb. 1, 2000) disclose a catalyst for conversion of Carbon monoxide with steam into carbon dioxide and hydrogen, Catalyst comprise of Co, Ni, Mo and/or W as oxides or sulfide as active components on TiO2 containing carrier and non-alkali metal element promoters used in the conversion of carbon monoxide with steam into carbon dioxide and hydrogen at 230 to 500 C under pressure between 0-10 MPa (absolute).
S. Hindin, et al., “High temperature stable catalyst composition and method for its preparation”, U.S. Pat. No. 4,056,489 (Nov. 1, 1977) disclose a high temperature stable catalyst composition and method for its preparation. The catalyst contains mostly platinum and platinum-palladium expensive product. The application is for atomized gasoline. The platinum group metal may be precipitated from solution, for example, as a sulfide by contact with hydrogen sulfide. The only limitation on the carrier liquids is that the liquids should not react with the platinum group metal compound and be removable by volatilization or decomposition upon subsequent heating and/or vacuum, which may be accomplished as part of the preparation or in the use of the completed catalyst composition. Suitable platinum group metal compounds are, for example, chloroplatinic acid, potassium platinum chloride, ammonium platinum thiocyanate, platinum tetramine hydroxide, platinum group metal chlorides, oxides, sulfides, and nitrates, platinum tetramine chloride, palladium tetramine chloride, sodium palladium chloride, hexamine rhodium chloride, and hexamine iridium chloride.
L. Polinski, et al., “High temperature-stable catalyst composition”, U.S. Pat. No. 4,220,559 (Sep. 2, 1980) discloses catalysts having good high temperature stability, which are particularly useful for carrying out high temperature reactions, such as combustion reactions at temperatures of the order of 1000°-1400° C., are disclosed. The catalytic active materials include precious metals, base metals or their oxides, or precious metals in combination with base metals, deposited on a catalyst slip or composite, which contains alumina in admixture with a metal oxide component. The metal oxide component consists of a mixture of strontium or barium oxide with molybdenum trioxide, zircon, silica, or stannous oxide or of a mixture of lanthanum with silica or stannous oxide. The slips or carrier compositions are calcified at a temperature of at least 500° C. before deposition of the precious metal or base metal material, and are characterized by having a surface area of at least 20 m2/g after calcination at a temperature of 1200° C. for 4 hours.
This invention relates to catalyst compositions, and in particular to catalyst compositions characterized by high stability, thereby maintaining good catalytic activity when used in reactions carried out at temperatures in excess of 1000° C. Catalyst compositions exhibiting a relatively high surface area per unit weight are desirable to allow the largest amount of reactants to contact the catalyst. Additionally, high surface area is important when the catalyst composition contains a precious metal such as platinum because of the cost of the metal and because of the dispersion required to prevent undue metal crystallite growth. It is desirable to retain this high surface area for long periods of use under severe conditions which might include reaction temperatures of the order of 1000-1400° C. Thus combustion reactions advantageously are carried out in the presence of such a catalyst at temperatures of 1200° C. or higher for extended periods.
Kato, “Catalyst for catalytic combustion”, U.S. Pat. No. 4,537,873 (Aug. 27, 1985), discloses a catalyst for catalytic combustion of a fuel used in an apparatus wherein high-temperature gases formed from said fuel are utilized, and particularly for catalytic combustion comprising a precious metal supported on a special carrier, said catalyst being very slight in lowering in performance even under high temperatures.
It is an object of this invention to provide a catalyst for catalytic combustion overcoming the defects of the prior art technique mentioned above, and exhibiting only a slight lowering of performance even used at high temperatures, said catalyst being obtained by carrying a precious metal on a carrier which can prevent the agglomeration of the precious metal component under high temperature conditions and exhibiting only a slight lowering of the specific surface area by sintering.
This invention provides a catalyst for catalytic combustion comprising precious metal particles supported on a carrier obtained from (a) titanium as a first component and (b) as a second component at least one metal oxide selected from the group consisting of oxides of magnesium, strontium, lanthanum, yttrium, cerium, zirconium, silicon and tin.
P. Duhaut, “Catalyst for hydrocarbon conversion”, U.S. Pat. No. 3,852,215 (Dec. 3, 1974) discloses a catalyst and process for converting or reforming, hydrocarbons. The catalyst contains an alumina carrier, platinum, iridium and at least one metal selected from the group consisting of scandium, yttrium, titanium, zirconium, hafnium, thorium and germanium.
F. Sergeys, “Stabilized automotive exhaust gas catalyst”, U.S. Pat. No. 3,903,020 (Sep. 2, 1975) discloses a process for preparing an ultra-stable catalyst capable of converting the noxious components in exhaust gases to innocuous entities is described. The catalyst is made by applying a solution of a salt of a noble metal such as palladium or platinum to a specially prepared support followed by activation at 1,800°-2,100° F. The special support is prepared by activating and stabilizing common support materials such as alumina with cerium oxide at high temperatures prior to application of the noble metal. The catalyst is stable to 2,100° F.
N. Komatsu, et al., “Catalyst for purifying exhaust gases”, U.S. Pat. No. 3,900,429 (Aug. 19, 1975) discloses a catalyst for purifying exhaust gases from internal combustion engines and the like which consists essentially of a particulate mixture of nickel particles and copper particles; nickel particles, copper particles and chromium particles; or nickel particles, copper particles, chromium particles and an oxide selected from the group consisting of yttrium oxide, titanium dioxide, lanthanum oxide and mixtures thereof, wherein said particulate mixture is sintered and at least partially oxidized
Romanian Patent 116547 (Mar. 30, 2001), “The process to obtain some ceramic products and the materials employed to make such products”, discloses a procedure to obtain ceramic products and a process to obtain such ceramic products. The process consist of sintering ceramic material made of mixture of kaolin, talc steatite, alumina, aluminum hydroxide and other materials at 700-1450 decree C. The ceramic material is subjected to 6-12 h of milling in a mill using corundum balls to granules of 18-36%. The milling process takes place in an acid solution of hydrochloric acid of 2-7% strength. The weight ratio of ceramic materials: corundum balls: acid solution is 3:2:2.
The ceramic material used for specific application will provide a superior caloric efficiency in the process of using natural gas. The ceramic material because of the catalytic properties will assure a smooth combustion without variation in the flame behavior.                The ecological efficiency are superior, the safety pressure of combustion is situated in the range of 5-10 mm column of water.        The caloric/energetic efficiency is in the range of 10-40%        
C. Clifford, et al., “Burner plaque with continuous channels”, U.S. Pat. No. 7,063,527 B2 (Jun. 20, 2006) discloses a ceramic burner plaque of predetermined thickness defined between first and second surface and through plurality of burner ports pass from one surface to other. The ports are arranged in offset rows and plurality of polygonal channels.
In a situation involving two species a reaction may only occur if they come into contact with each other. They first have to collide, and then they may react.
It is not enough for the two species to collide—they have to collide in just the right way, and they have to collide with enough energy/speed for chemical bonds to break. Collisions result only in a reaction if the particles collide with enough energy to get the reaction started. This minimum energy required is called the activation energy for the reaction.
To increase the rate of a reaction the number of successful collisions must be increase. One possible way of doing this is to provide an alternative way for the reaction to occur that has a lower activation energy. In the case of combustion on a catalyst, the hydrocarbon is adsorbed on the catalyst surface and will easily react with the very mobile oxygen from the catalyst.
The activation energy is obtained by consuming a portion of the overall energy generated by combustion. The lower the activation energy the more efficient the combustion will be.
In hydrocarbon combustion reactions with air, nitrogen (which is about 80% of the air composition) is in competition with the hydrocarbons for oxygen. Nitrogen, by reacting with oxygen, will use heat to provide for the activation energy of its reaction with oxygen, lowering the combustion efficiency. The unwanted reaction between nitrogen and oxygen generate nitrous oxides and will lower the available oxygen needed to react with the hydrocarbons. Quite a number of the hydrocarbon molecules will not be part of the combustion reaction because no oxygen molecules are available, further lowering the combustion efficiency and increasing the carbon footprint. The unwanted reaction of nitrogen with oxygen is also the main source of emission pollution in this particular type of combustion.
Therefore, a highly efficient, stable and economically effective catalyst is desirable to increase the efficiency of combustion reactions.